The aim of this project is to evaluate the impact of physical fitness and exercise habits on health status and functional capability in men and women throughout the life span. Specific questions to be addressed include: does regular exercise promote health, is a change in physical fitness associated with a change in health status, what are the characteristics of individuals who change and maintain change in their exercise patterns, and does regular exercise affect the age-related decline in physical fitness and functional capacity? Hypotheses relating to these aims will be tested by secondary data analysis on a large data base developed over the last ten years on a group of patients attending a preventive medicine clinic. Data from an initial clinic examination are available on approximately 24,000 adults (80% men, 20% women) between the ages of 18 and 75. Subset of this group have been followed with repeat clinic visits; for example, 8,000 patients have had two or more examinations. Length of follow-up ranges from six months to ten years. In addition, follow-up mail surveys on current health status and health habits were obtained in 1982. More than 13,000 surveys have been returned and are available for analysis. Data from clinic visits include extensive medical history, physical examination, and clinical measures including a maximum graded exercise test as an objective index of physical fitness. Additional clinic data are available on health habits and demographic characteristics. The follow-up mail survey provides data on health habits and current health status. Both cross-sectional and longitudinal analyses will be performed. The large sample size and broad range of variables will permit complex multivariate modeling to test hypotheses. Although the select nature of the population will inhibit generalization of the results to the entire population, we will be able to develop models for testing in other subgroups. The research team has clinical experience in health behavior change and assessment of health status; expertise in exercise physiology; experience in analyzing interactions between clinical variables, exercise, and behavioral data; and expertise in biostatistical and methodological techniques to evaluate the complex interactions between health behavior, health status, and functional ability underlying the hypotheses to be tested in this study.